It won't hurt them. Protein percentage a bit different but not much. Can you augment their diet with a bit of cracked corn and fresh greens? (ie; leaf lettuce or Romaine? not sure of your location, but if dandelion greens are still available where you are, they would love that). What is the nature of their injury? Do you need a Migratory Bird Permit to keep them in your area?

I currently give the chickens greens so as long as they allow the geese to eat they should be alright. Not sure what the injuries are. All that I know is that they are not able to fly right now. One of them flaps it's wings but does not fly and the other just sits down when you get close. The plan is to try to get them better so I can release them on my pond. Believe me I really don't want any geese right now.

I don't know where you live but I would contact a wildlife specialist. Canadian geese are migortory fowl. Here in Michigan it is not uncommon to see them all year round if they have access to open water. I would keep them separated from your chicken flock just in case they may have something contagious. It is unusal for them to be separated from their flock. It sounds like they may be a mated pair. Do you think the one may of gotten shot? Good luck and keep us posted. I don't know if your local DNR would be interested.